1. Field of the Invention
The present invention relates to an array substrate, a method of manufacturing the array substrate and a liquid crystal display panel including the array substrate. More particularly, the present invention relates to an array substrate of decreased pixel defect, a method of manufacturing the array substrate and liquid crystal display panel including the array substrate.
2. Description of the Related Art
In general, a liquid crystal display apparatus includes a liquid crystal display panel and a driving part to drive the liquid crystal display panel. The liquid crystal display panel includes an array substrate, a color filter substrate and a liquid crystal layer disposed between the array substrate and the color filter substrate.
The array substrate includes a plurality of data lines and gate lines that are usually arranged in a grid pattern, and a plurality of pixel areas defined by the data and the gate lines. A switching element, a liquid crystal capacitor and a storage capacitor are formed in the pixel area.
A gate electrode of the switching element is connected to the gate line. A source electrode of the switching element is connected to the data line. A drain electrode of the switching element is connected to a pixel electrode that functions as a first electrode of the liquid crystal capacitor. The storage capacitor is defined by the gate electrode and the pixel electrode.
The color filter substrate corresponds to the pixel area and includes a color filter pattern and a common electrode that functions as a second electrode of the liquid crystal capacitor.
A contact hole is formed by partially etching a passivation layer coated on the drain electrode to electrically connect the drain electrode and the pixel electrode.
In etching a passivation layer, the semiconductor layer that is formed beneath the drain electrode is sometimes undercut from an overetching of the passivation layer. The undercutting induces subsidence and separation of the drain electrode. When this happens, the drain electrode does not apply an electric field to the pixel electrode, and the pixel becomes defective.